Ultrafast polarization control of zero-bias photocurrent and terahertz emission in hybrid organic perovskites

TL;DR

This study demonstrates ultrafast polarization-controlled photocurrent and terahertz emission in methylammonium lead iodide, revealing insights into light-matter interactions and potential for advanced solar and spintronic devices.

Contribution

It provides the first observation of polarization-dependent bulk photovoltaic effects in MAPI at room temperature, linking these effects to device physics and future applications.

Findings

Ultrafast photocurrent and THz emission observed in MAPI.

Polarization dependence consistent with bulk photovoltaic effect.

Potential for exceeding Shockley-Queisser limit in perovskite solar cells.

Abstract

Methylammonium lead iodide (MAPI) is a benchmark hybrid organic perovskite material, which is used for the low-cost, printed solar cells with over 20 percent power conversion efficiency. Yet, the nature of light-matter interaction in MAPI as well as the exact physical mechanism behind device operation is currently debated. Here we report room temperature, ultrafast photocurrent and freespace terahertz (THz) emission generation from unbiased MAPI induced by 150 fs light pulses. Polarization dependence of the observed photoresponse is consistent with the Bulk Photovoltaic Effect (BPVE) caused by a combination of injection and shift currents. We believe that this observation of can shed light on low recombination, and long carrier diffusion lengths due to indirect bandgap. Moreover, ballistic by nature shift and injection BPVE photocurrents may enable third generation perovskite solar cells with efficiency that exceed the Shockley_Queisser limit. Our observations also open new venues for perovskite spintronics and tunable THz sources.